Left Behind (An Undertale Fanfic)
by Greg Jonson
Summary: /POST-PACIFIST\ The prophecy has been fulfilled and the monsters were finally set free. Everyone is struggling to slowly assimilate into the new world... But is that actually everybody? (I will finish this story eventually, but now it's on pause.)
1. Chapter 1

_For any of you who haven't read one of my other fanfics called His Story, I made a deal with my readers there that if I fail to post a new chapter within a month since a previous one, I will have to write a short story about Jerry. Well, I did manage to fail the deadline about halfway through the fanfic, and now I'm keeping my promise with this. :D_

* * *

 **Left Behind (Part 1/3)**

For the first few months of the monsters' freedom, education was a bit of a problem. The humans who understandably weren't ready for their arrival insisted that until the beginning of next school year, monsters should have their own separate school. Aside from assimilating purposes, it was quite reasonable because the human and monster education systems were pretty different. As a result, the children were offered a brief introduction to the subjects that were taught on the surface, and were expected to take comparative exams by the end of Spring to see if they were ready to enter human schools next school year.

„It's so stupid!" Snowdrake complained. „Why do we have to learn everything about human history? It's so much!"

„Come on, it's not so bad," Monster Kid consoled him. „Just take the mevi... medev... me-di-e-val times, for example. Humans used to fight constantly! With swords and pikes and bows and arrows! And castles! How cool is that?"

"Yeah, one time they even attacked _us_ , remember?" said Ice Cap. "I still can't believe how lucky we are that they don't want to kill everyone that they meet anymore."

Snowy, Kid and Ice were sitting under a tree on the outskirt of the monsters' temporary camp outside the human city. Before the monster integration would begin to bring some results, they had to either live in tents, or back inside the mountain -and noone wanted to return there.

Much to everybody's surprise, the humans weren't as much afraid of them as they were curious. Aside from government officials, some bystanders could occasionally be seen standing around watching whatever was going on in the camp. By the looks of it, they were mostly surprised that monsters were very much like them except obviously for their appearance. A few human children have already overcome their constraint and started to make some new friends among the monster younglings.

The three of them, however, intended to stay away from them for today because their history exam was right around the corner. Miss Toriel who took the responsibility for human subjects told them that if they were going to become a part of the human world, they should know how it became what it was. Their brief introduction to this subject emphasised the time period between the monsters' imprionment and freedom so that they could understand how much the humans and their world have changed since then.

"It's strange, isn't it?" asked Ice while closing one of the few books that they had lying around them. "Humans have always only been looking for differences that they could then eradicate. Continents, states, wealth, religion, race. Seems like human history is actually the history of war."

"I know, it's awesome, right?" Kid said excitedly. "Constant action, explosions and knights in shiny armor! That's rad!"

"Have you heard of the atomic bombs?" Ice cap asked darkly and opened the book again. He shuffled a few pages before he found what he was looking for, and then read out loud: "'On August 6 and August 9, the two bombs were dropped on Hiroshima and Nagasaki. The bombings and subsequent radiation caused the death of more than 200,000 civilians.' Two hundred thousand, just like that." Ice snapped his fingers. "Does that sound _rad_ to you?"

Monster Kid's expression changed as he realised the impact of what his friend just told him. "Are humans really that cruel?"

"No, no," Ice soothed him when he saw that Kid was scared. "I mean, they kinda... had to do it back then. To make the other guys surrender, to prevent even more people from dying. That's what I've read, anyway," he sighed.

"Wow, Ice," Drake joined the discussion. "When have you become so dark?"

"I'm not dark, I'm just... thinking." The monster looked up at the sky. "After I met the human that freed us, I started to think more about us monsters. I realised that each and every one of us is as different as it can get, and yet we're all united and act like one gigantic family. And now with all that's in these books, I find it strange that humans were always looking for reasons to hate each other, rather than realising everything that connects them."

Kid sniffed. "Aren't you afraid they're just gonna destroy us again?"

"Not really," Ice answered and smiled decisively. "The humans we've met so far aren't the same as those seventy years ago. They're doing everything they can to give us a warm welcome."

His friend took a deep breath and smiled back. "Okay."

"And hey, here's another great thing about us being free," said Snowy. "I get to celebrate my 14th birthday on the surface!"

"Yo, that's great! When?" Kid asked.

"Next Monday. I'm thinking party for our entire class, what do you say?"

"Heck yeah, dude!"

"I'm in!" Ice agreed. "All eleven of us, that's gonna be awesome!"

"Ten," Drake corrected him.

"Eleven, dude. There's always been eleven of us."

"Really? I'm pretty sure there's only ten of us in class."

"Okay, let's just count everyone. There's us, that's three..."

"The Temmie sisters and Bob..."

"That's seven, then there's Chilldrake..."

"Sammy and Sally, and then, hmmm... We're missing someone else..."

"Jerry," said Monster Kid.

"Oh yeah, Jerry!" Ice cheered, but frowned quickly at Snowdrake. "Are you gonna invite him, too?"

"I mean, I kinda have to. I don't want him to feel left out," he answered, but didn't seem happy about it.

"Guys," Kid spoke up again. "I don't think I've _seen_ Jerry since we left the underground."

His friends thought for a second. "Me neither," said Ice.

"I think that's why I thought there were only ten of us in class," Drake shook his head. "But he was with us back there, wasn't he?"

"Like you need to remind us," Ice cap grunted. "That guy was **everywhere**. He always had to stick his nose into everything."

"But what's up with him now?" Kid asked. "Is he sick? I think we should visit him, see how he's doing."

"Maybe we should. Do any of you know where he lives?" said Snowy, and they all went silent, looking at each other.

"Come to think of it, I don't even know where he lived in Snowdin," Ice said eventually. "Did you?"

"No."

"Nope."

"We should ask some adults, then," he suggested. "This is beginning to be a little strange."

* * *

Not even did none of the adults know where Jerry was; most of them didn't even know _who_ he was. The three kids waited long to admit it, but they realised that they were seriously worried about the lost monster.

"So get this," said Kid in the evening; "I went to mister Gerson, told him we're missing a friend, and described him as best I could. He told me he didn't see him when we left the underground. He says he's old and his memory isn't what it used to be, but..." He gulped. "I know him, he never forgets a face. If he says he didn't see Jerry leave with us, then... He didn't leave with us."

Ice and Drake looked at each other.

"So you're suggesting Jerry might have stayed behind?" Ice asked.

"I think so. I mean, none of you told him we were leaving, right?"

"No, I... forgot," Snowy mumbled and his face turned red.

"We all did, I suppose," his friend continued. "Guys, we gotta come back for him."

"What!" Kid exclaimed.

"Are you serious?" said Drake. "We just got out of that... place... and you wanna go back?"

"All the way to Snowdin Forest if we have to."

"Ice, I know Jerry doesn't deserve to be left behind, but... I really don't wanna go there again!" Snowy whined.

"Hey, don't be a baby! We've been there all our lives, we can handle coming back for a few hours again. Besides, I'm not telling **my** parents that we've abandoned a kid in the underground."

"Right, you're... you're right. We have to do this." Drake turned towards Monster Kid. "You with us, dude?"

"W-well, I don't like this, but..." Kid jumped up. "It's what Undyne would do, right? She'd never let someone down like that, she'd run down there as fast as she can and bring Jerry back before you know it!"

"Uh, sure, that's one way to look at it." Ice looked at his friends and continued in a conspirational tone. "Alright, you know our parents won't let us just wander off into the mountain like that. That means we gotta leave in secret. At night."

"How long before we get back? Can we make it in time?" Snowdrake asked.

"I think so," Ice assured him quickly to cover up the fact that he actually had no idea. "We'll meet at the entrance at ten thirty, does that work for you?"

"Hey," a fourth voice suddenly spoke up nearby, causing the three friends to flinch and turn their heads towards the intruder. "I don't mean to be rude, but you guys should really keep an eye out for any adults when you're making plans like that."

"Oh, it's you," Ice Cap breathed out and smiled. "You scared the heck outta me."

"Woah, were you eavesdropping on us?" said Snowy. "Speaking of being rude..."

Frisk came closer and stood above them. "Oh no, I was just walking around and I saw you and thought I'd stop by to see what you guys are up to. I only heard, like, the last four sentences. Why do you wanna go back?"

"Oh, we think our friend might have stayed behind so we want to bring him back," Monster Kid answered enthusiastically before his two friends could say anything.

"Dude!" Drake hissed.

"What? We can trust Frisk, right, Frisk?"

The human girl's expression shifted. "Are you serious? There's a kid in the underground and nobody noticed yet? How's this possible?"

"Well..." said Ice hesitantly; "he was -he _is_ kind of a... jerk. I don't... I don't think anyone has... missed him."

Frisk frowned. "That's horrible."

"Alright, save it, we feel bad already," said Snowdrake. "We'll just go down there and come back with him before anyone notices we're even gone and everything will be f-"

"No, you won't," she interrupted him.

"Excuse us?" he said back in surprise. "What're you gonna do, tell the adults?"

"You wouldn't do that, right?" Kid asked and made puppy eyes at Frisk.

She smiled. "You don't understand. It's not the _leaving_ part that I'm questioning, it's the part where you manage to come back before your parents find out you're gone. There's no way you can walk through the whole underground _and_ back in one night."

"Oh, shoot." Ice scratched his head worriedly. "Well, we don't really have a choice, do we? We have to try."

"But," Frisk said in a mysterious voice and sat down with the three monsters, "there might be enough time if you only go one direction."

"Er, what? We're not gonna stay there, if that's what you're thinking," Snowy replied.

"No, dude," she proceeded. "What I'm trying to say is, you're lucky that I happen to know a shortcut."

* * *

 _To be continued._


	2. Chapter 2

_Oops. Looks like **someone** wants to be a part of this story too. That means this fanfic will be longer than I expected. :D_

* * *

 **Left Behind (Part 2/3)**

„Careful," Frisk hissed. „The fall won't necessarily kill you, but it still hurts like hell."

„Fine, geez," Ice Cap whispered back and panted. „I'm not used to this kind of exercise."

„Would you hurry? Why do I have to be the only one with wings?" Drake shouted from above.

„Well, 'wings'," said Monster Kid. „More like gliders."

„Yeah, but still. It means I have to sit here until you guys take your sweet time to _climb_ down here."

"You could have stayed on the surface, noone would hold that against you," Frisk retorted.

They all left the starry night behind and climbed down into the underground. The human told the three friends that this was the path through which she accidentally fell down some time ago. What was then a sudden, unfortunate hole in the ground now served as their entrance; Frisk explained that the hole lead into the ruins of the first Home, meaning it wasn't as far from the Snowdin Forest as if they'd have to walk all the way from the main cavern.

The hardest part so far was to obtain a rope without anyone noticing. Frisk and Kid took the opportunity to go into town and see if they could simply buy it somewhere, only to find out that the one shop they could find was closed already. Luckily, the human was a good friend with Sans The Skeleton; when she asked him to obtain a rope from the shop without any questions, he somehow did. His only request was that they would come see him early in the morning so that he could return it before the shopkeeper notices.

Frisk originally intended to ask Sans to go look for Jerry instead of the three monsters in the first place, but they convinced her otherwise, saying that a) Jerry was their responsibility and they couldn't let anyone else just do their job, and that b) they still didn't want anyone to know that they left him in the underground all alone.

"Mom used to talk about this place," said Snowy after a while to break the silence. "It was the first monster city underground. She was a child when there was... I think an earthquake or something? Most monsters decided to move higher towards the surface. Some folks were stopping along the way to build their own settlements."

"And that's how our families got to Snowdin?" Kid asked from above.

"Kinda. I mean, there wasn't a Snowdin yet when they moved there, I think."

The rope made a desperate scrunching sound.

"Um, guys," Ice told them slowly. "Are you sure this rope is supposed to hold us all?"

"Naah, we can't be _that_ stupid, right?" Frisk said regretfully.

Next thing they knew, they were all piled up on the bed of flowers at the cavern's floor, aching all over their bodies and intertwined with each other as well as the remaining piece of rope.

"It appears we can," said Monster Kid who was lying on top of Ice Cap and Frisk.

"Ow, get off me, guys!" Drake mumbled somewhere underneath all of them. They gathered around groaning and caressing different parts of their hurting bodies.

"Next time we do something like this," Snowy swore, "I'll make sure I watch from a **really** big distance."

"Not that I'd predict this would happen, but standing right under us wasn't smart," Ice retorted.

Frisk smiled nervously in an attempt to lighten the mood. "I told you the fall hurts."

"Gee, thanks for the heads up," said Drake. "I hope Jerry will appreciate what we had to go through to get him."

"Speaking of which," Frisk looked forwards at the cave's exit; "we should get going. We don't have all night."

The four children set off on their way through the ruins. They walked slowly at first, but as their muscles were forgetting about the impact, they gained some speed again.

The area was cold, dark and empty. Much emptier than upon Frisk's first visit. But at least the puzzles were all solved.

"Hold on," she said after some time. " I have to check something in here."

She ran into one of the smaller side caves. Her head popped out a few seconds later.

"Are you guys hungry?" she asked.

"Why?" Ice replied.

Frisk emerged from the cavern with a half-empty bowl of candy in her hands. " _These_ are still here, if you want. I don't think anyone will be needing these down here anymore."

"Wow!" Kid exclaimed and approached her. She grinned and put a piece of candy in his mouth.

"Why's there a bowl of candy here, in the middle of nowhere?" Drake wanted to know before he took one himself.

"Well, Tor... Mom told me that her children used to play here a lot, so she had this set in here for them." Frisk shook her head sadly. "After everything that happened... Let's just say old habbits die hard."

She suddenly turned around. "Can you give me a second, please? Just keep walking, I'll catch up with you later."

Kid opened his mouth to ask questions, but caught the look Ice was giving him soon enough to remain silent.

"Okay. Don't take too long," Ice Cap said, and the three monsters walked away.

"What?" Monster Kid asked when they were far enough.

"Dude, I think she cried," Ice explained. "Whatever it is, Frisk didn't want us to see it."

"Um," said Snowy; "do you know what she was talking about? Miss Toriel's children?"

"I don't. Come to think of it, I didn't even know she _had_ any children," Kid frowned.

"Me neither. But I mean... What was miss Toriel even doing before we met her? Someone told me she used to be Fluffybun's wife..."

* * *

Frisk wiped away the few tears that escaped her eyes and forced herself to stop.

"I'm... sorry," she said to the cave. "It's already happened, hasn't it? I thought that when you weren't there, you probably aren't... yourself anymore."

A small shadow popped out in front of her.

"I'm as myself as I can be right now, thank you very much."

Flowey stretched, and then noticed Frisk's wet eyes.

"Hey, what's the matter? And by the way, how did you know I was here?"

She smiled. "Four kids appear in the underground after two months? Of course you'd follow us, you wanted to know what's going on."

"Yes. And I'll give you this, when you all fell down... It was hilarious." The flower laughed insencerely. "But I still don't know _what_ is going on. And because you stopped to talk to me, perhaps you'd like to explain?"

Frisk looked at him quietly.

"Frisk? You're kinda freaking me o-"

"Come with us, Flowey."

His jaw dropped. "What?"

"Come with us." She kneeled to have his confused face on her level. "We came down here because one monster has been left behind, we wanted to take him to the surface. But... Now I realised that Jerry's not the only one."

"Frisk..." Flowey smiled, and this time, she could feel it was genuine. "I thought we went through this already. I can't go back."

"When you still had Asriel's body, I understood your reasons. You didn't want to come before your parents only for them to see you... die again." Frisk sighed. "But now... It's not the same. You're just another friend that deserves-"

"I'm nobody's friend," the flower interrupted her. "I don't need anyone's pity."

"Seriously? After everything that happened?"

"Frisk," Flowey looked in her eyes; "I told you, you can't think of me as Asriel anymore. He's gone. I'm just... a bitter, cold-blooded, emotionless flower. So why in bloody hell would you want to bring me to the surface?"

"Because I believe nobody should be alone."

He tilted his head to the side. "What do you mean?"

Frisk thought for a second. "Would you rather spend the rest of your life here, with no company whatsoever, knowing solutions to every puzzle and the story of every book in the underground? There's nothing left for you anymore, Flowey. Up there... There's a new opportunity for all of us, even you."

Flowey remained silent.

"I know that you're not Asriel, but... you owe it to him."

Their eyes met again; they stared each other down for some time before Flowey finally opened his mouth.

* * *

"Now what?" Kid asked. The three of them found themselves on a crossroad and didn't know where to go next.

"We should split," Ice started to organize them. "One of us goes that way, the other one over there, and... Kid, you stay with one of us."

"Hey! I can help, too!"

"No offense, but you tend to get into trouble too easily," Ice grinned. "You can't get lost around here."

"I won't!"

"Says the one who was getting lost in the forest all the time," said Snowdrake.

"That's not my fault!" Kid exclaimed. "The trees literally look all the same!"

"Well these caves all look the same to _me_ ," Snowy looked around.

"Fine! Why don't we just wait for Frisk, then? She knows where to go," Kid proposed.

"Yeah," Ice agreed. "She said she'd catch up anyway, and it's been like... a lot of time. She should be here any moment now."

They listened.

"Actually, I think I hear footsteps," Kid said.

"I hear them too. Frisk is probably just around the corner," Snowy rejoiced. "Let's go meet with her!"

"Yeah! I hope she didn't eat all the candy," Kid laughed.

As it turned out, the three monsters were too late.

"Sorry, guys," Frisk shrudded. "We had to eat all the candy."

"We?" Cap asked and looked around. There was noone else except for Frisk. The bowl was, however, very much candy-less; a yellow flower in a shallow layer of ground has taken its place. "What do you mean, you and this flower?"

"Hey, I'm not proud of it either, jerk," the flower spoke. The three monsters jumped up in shock.

"Whoa, what's that?" Snowy asked, his eyes widened.

"More like _who's_ that, don't you think?" said the flower. It was obviously happy that it scared them all like that.

"This is Flowey, an old friend," Frisk explained. "I convinced him to join us."

"And no comments about the bowl," Flowey added. "It's humiliating enough as it is, and if anyone as much as thinks about asking anything, they're dead on the spot."

"He's a little grumpy, but he won't hurt you," the human clarified.

"Yes, I will," the flower whispered and winked.

"How is this possible?" Kid asked.

"Seriously, guys," Frisk frowned and covered the flower's mouth with her hand; "we don't have time for this if we want to make it out in time. So please, just be cool with it. Flowey, stop biting me."

"Fine, fine," Ice Cap gave up. "Let's go."

The human smiled again. "It's not that far. There's an old house right around the corner, with a secret path right to Snowdin forest. We'll be there in no time."

"How do you know about all this, Frisk?" said Snowy when the group walked past the crossroad where the monsters were stuck before.

"I guess I was just lucky enough to meet the right people in the right time," Frisk answered. Flowey snickered quietly.


End file.
